Aquifer systems of Epirus, Greece: An overview

Abstract

The Epirus region covers an area of 9385 km2 and displays one of the highest surpluses in water regime of the country. The annual renewable water supplies of the major aquifer systems are 2880x106 m3 and the total volume of the available groundwater 3220x106 m3. 2390x106 m3 are in storage in the karst aquifers and cover 75% of the Epirus water demand. Major elements analyses performed on 2310 groundwater samples from the study area showed that they are mainly of good quality and can be classified into three major groups. It should be noted that a significant percentage of the available groundwater is degraded, due to high SO4 2- concentrations. In the coastal aquifer systems either porous or karst ones that are in hydraulic connection with the sea, occur active and passive seawater intrusion respectively. In those areas a small percentage of the groundwater is brackish. Elevated NO3 - concentrations ranging from 80 to 150 mg/L were observed in many boreholes located in Preveza peninsula. Groundwater also from several springs and boreholes displays locally high nitrate content that varies from 25 to 50 mg/L.